1. Field of the Invention
The present invention relates to an image forming apparatus, and a liquid removal capability setting method, and more particularly, to an inkjet recording apparatus or other image forming apparatuses which form images of high quality by efficiently removing surplus liquid on a recording medium, and to a liquid removal method for same.
2. Description of the Related Art
In image forming apparatuses, such as inkjet recording apparatuses, an image is formed on a recording medium by using liquid ink in which coloring material and additives are mixed into a solvent, such as water, alcohol, or the like. Liquid (ink solvent) remains on the surface of the recording medium on which the image is formed, and this can be the cause of image degradation (image defects), rear-side image transfer, cockling, and the like. In an inkjet recording apparatus, it is necessary to swiftly remove the liquid remaining on the recording medium in this way, and various means of achieving this have been devised. In particular, in systems which promote the fixing of the ink by causing the coloring material contained in the ink to become insoluble, or causing the coloring material to aggregate, by making the ink to react with a treatment liquid on the recording medium, the amount of liquid deposited onto the recording medium is high, and there is a strong need for the liquid to be removed.
Japanese Patent Application Publication No. 2001-179959 discloses an ink absorbing body and an image forming apparatus and method using the ink absorbing body, in which the ink absorbing body comprises a liquid solvent absorbing body and a separating member that covers at least partially the surface of the liquid solvent absorbing body and allows the ink solvent to pass, while having separating properties with respect to the coloring material of the ink. When ink is deposited on a sheet, the liquid solvent absorbing body is placed in closed proximity to a portion of the sheet through the separating member, and the liquid solvent is absorbed into the liquid solvent absorbing body through the separating member, in such a manner that the coloring material and the liquid solvent of the liquid ink on the sheet are mutually separated. Furthermore, there is also a composition in which a liquid volume sensor which determines the liquid volume inside a high polymer absorbing body is provided, and when the sensor value has reached a prescribed value, then a squeezing mechanism is operated.
Japanese Patent Application Publication No. 2003-136689 discloses an inkjet process including removal of excess liquid from an intermediate member, in which a primary image formed by an inkjet device is transferred to a receiving member in a transfer process zone, and in this composition, a concentrated image is formed by an image concentrating process after the primary image is formed, and a portion of the carrier liquid is removed from the concentrated image in an excess liquid removal process zone.
However, in the related art, the liquid is removed by placing an absorbing body in contact with the recording medium and pressing the absorbing body against the recording medium, and this is insufficient for handling recording media of different types, thicknesses, surface characteristics, and the like. For example, since an absorbing body is pressed against the recording medium at a prescribed pressure when removing the liquid on the recording medium, regardless of the type, thickness or surface properties of the recording medium, and the like, then in a recording medium having low surface smoothness, the ink coloring material is more liable to adhere to the absorbing body, compared to a recording-medium having high smoothness, and hence there is a risk of image defects, reduced density, and a concern that coloring material which once becomes attached to the absorbing body adheres to another sheet of recording medium.
In the ink absorbing body and image forming apparatus and method using the ink absorbing body described in Japanese Patent Application Publication No. 2001-179959, and the transfer type inkjet printer described in Japanese Patent Application Publication No. 2003-136689, there is no disclosure regarding the absorption force of the ink absorbing body, or restriction of this force, and hence there is a risk of ink coloring material becoming attached to the ink absorbing body.